Apparatus for treating refractory ores.



No. 796,585. PATBNTED AUG. 8, 1905 A J. LEEDE.

APPARATUS FOR TREATING REFRACTORY ORES.

APPLIOATION FILED NOV. 7,1904.

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No. 796,585. PATENTED AUG. 8, 1905.

.LLEEDE.

APPARATUS FOR TREATING REFRACTORY ORES.

APPLICATION I'ILED NOV. 7.1904.

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PATENTED AUG. 8, 1905.

J. LEEDE. APPARATUS FOR TREATING REFRACTORY DRES- APPLIOA'IION FILEDNOV. 7,1904.

5 SHEETS-SHEET 8.

51140094 fat Juu us LE0 No. 796,585. PATENTED AUG. 8, 1905.

J. LEEDE.

APPARATUS FOR TREATING REFRACTORY ORES.

APPLICATION FILED NOV. 7,1904.

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W. W atmnw UNITED STATES PATENT OFFICE.

APPARATUS FOR TREATING REFRACTORY ORES.

Specification of Letters Patent.

Patented Aug. 8, 1905.

Application filed November 7, 1904. Serial No. 231,791.

To (071/ wit/mt it nuty conceit-'2..-

Be it known that I, JULIUs Lnnnn, a citizen of the United States,residing in the city of Baltimore and State of lWIaryland,haveinventedcertain new and useful Improvements in Apparatus for Treating RefractoryOres,

of which the following is a full, clear, and exphorets of iron, lead,copper, &c., containing the precious metals.

The object of the invention is to provide novel means for subjecting theore to an oxidizing-flame in a furnace and simultaneously supplyingthereto a cooling alkaline solution, whereby the ore is calcined and theformation of slimes which interfere with the subsequent treatment isprevented, whereby the formation of sulfates or acids which produce alilm over the precious metals and prevent the successful action ofchlorin and mercury thereon is prevented, whereby the base metals andother oxidizable compounds are oxidized, and whereby the ore issubjected to a chilling action, which serves to disintegrate the same,keep the temperature down, and prevent the volatilization of theprecious metals.

It is a well-known fact that in the presence of tellurium and other basemetals gold and silver volatilize at relatively low temperatures, and itis also known that roasting is the usual and most approved way foreliminating these base metals to prepare the ores for subsequenttreatment. hen the ores are roasted, however, a large portion of theprecious metals is volat-ilized and carried off in the fumes. This isavoided by the use of my apparatus, as a suflicient oxidizing heat isemployed for oxidizing the base metals, which heat is held under controland prevented from rising to such a degree as to volatilize the gold andsilver. Furthermore, it is Well known that when the ores are roastedaccording to the usual methods the precious metals become coated with afilm of silicon or of sulfates, which prevents the further successfultreatment of the ore by other reagents.

The details of the invention will hereinafter appear, and the novelfeatures thereof will be set forth in the claims.

In the drawings forming part of the specification, Figure l is anelevation, partly in section, of the apparatus as a whole. Fig. 2 is avertical central section of the furnace. Fig. 3 is atop plan view of thesame, with the cover or dome removed. Fig. i is a side elevation of thefurnace. Fig. 5 is a detail sectional view of the distributer. for thealkaline reagent. Fig. 6 is a cross-section on the line 6 6 of Fig. 5.Fig. 7 is an end view of the distributer. Fig. 8 is a detail sectionalview on thelineS 8 of Fig. 5. Fig. 9 is a plan view of thefurnace-bottom with sections of the same removed. Fig. 10 is a detailsectional view on the line 10 10 of Fig. 9. Fig. 11 is a section on theline 11 11 of Fig. 9. Fig. 12 is a longitudinal sectional view of one ofthe burners or twyers; and Fig. 13 is a section on the line 13 13 ofFig. 12, showing aplurality of the burners clamped together.

Like reference-numerals indicate like parts in the different views.

My improved apparatus comprises a furnace made up of a base-plate 1,supported in raised position upon the uprights 2 and having built upupon it the sides 3 and top 4 of fire-brick. The said base-plate hasbeen shown as rectangular in shape and provided with anupwardly-extending flange 5 around its outer edge. It is preferably madeof a metal casting bolted or otherwise secured to the uprights 2; but itis obvious that the same may be made of other material and be otherwiseshaped and supported. At the center of the base-plate 1 is formed acircular opening 6, Within which the bottom 7 of the furnace fits. Thesaid bottom is mounted for rotary movement, is capable of being raisedand lowered, and is supported upon a carriage or truck 8, by means ofwhich it may be moved bodily up to and away from the body of thefurnace. The furnace is mounted in elevated position in order to providefor these movements of said bottom. The truck or carriage 8 is providedwith Wheels 9, which move upon the rails 10, located between theuprights 2, beneath the base-plate 1, and extending to any suitablepoint.

Mounted in suitable bearings on the carriage 8 is a vertically-disposedshaft 11, the said shaft carrying a horizontally-disposed worm-gear 12,adapted to mesh with a worm 13, mounted in a suitable bracket or support1a and driven in any suitable manner. The

said worm is fixed in position, and an adjustable stop is provided forlimiting the movement of the carriage 8 upon the rails 10 anddetermining the proper position of said carriage, so that the gear 12will be in mesh with the worm 13 and so that the bottom 7 will bedirectly beneath the opening 6 in the baseplate 1. Ball-bearings 16 areprovided between the gear 12 and the carriage 8, and said gear has a keyconnection 17 with the shaft 11, so that while said shaft is rotated bysaid gear it is also capable of vertical movement independent of saidgear.

Secured to the upper end of the shaft 11 is a sleeve 18, upon which arecast or otherwise secured the outwardly and upwardly curved arms 19, thelatter having bolted or otherwise secured to them a hollow frame havinga central circular portion 20 and radiating ribs 21. These ribs areformed with recesses providing the shoulders 22 and have lugs 23 formedupon them. Within said recesses and supported upon said shoulders arethe triangular plates 24, the same being secured to said ribs by boltsextending through said lugs. The said triangular plates or sections 24and the ribs 21 form the bottom 7 of the furnace, each of said plates orsections being provided with an upwardly-projecting flange 25 around itsouter edge. Upon the central circular portion 20 of the hollow framereferred to is secured an upwardly-extending hollow thimble orprojection 26, which forms, with the flanges 25, an annular receptaclein the bottom 7. One of the sections 24 of said bottom is provided withan opening for the discharge of the contents of the furnace, the saidopening being normally closed by a hinged door or trap 27. This door ispivoted at its outer edge and is adapted to swing downwardly, being heldin its normal raised position in any suitable manner. I have shown theinner end of said door, however, provided with a-lug or projection 28,adapted to receive a removable bolt 29, extending through saidprojection and through a lug on the under side of the section 24.

In order to provide for the elevation of the rotating bottom or table 7of the furnace, I employ a hydraulic jack, shown in Fig. 2 of thedrawings as consisting of a cylinder 30, having apiston 31 therein, witha plunger 32 on said piston adapted to engage the lower end of the shaft11 and having a pipe 33 leading into the lower end thereof through whichwater or other liquid under pressure may be passed. This jack is ofcourse located beneath the shaft 11 when the parts are in the positionsin which they are shown in Figs. 1, 2, and 4 of the drawings.

Arranged within the combustion-chamber of the furnace are a series ofburners or twyers 34, the same being shown in two rows, with the membersof each row parallel to each other in line with those in the other rowand terminating at their inner ends'a short distance from thelongitudinal central line of the furnace. These twyers or burners areall connected with a main supply-pipe 35 for fuel through the branches36 36 of said pipe,

which extend along the opposite sides of the i furnace. The fuel-supplypipe 35 has been shown as extending from a gas-producer 37, theparticular construction of which will not be herein described as thesame forms the subject for a separate application for patent. It issuflicient to say with respect to said gasproducer that avalve or damper38 is provided at the rear end of the retort whose position may beadjusted by means of the screwrod 39 for admitting to and mixing withthe gas before it leaves the generator any desired proportion of air, sothat exactly the kind of oxidizing-flame which is desired may beproduced at the burners 34. The said burners are provided withwater-jackets and are so constructed that any one or more of them may bedisconnected from the supply-pipes 36 without the necessity forcompletely dismantling the whole apparatus or removing any other parts.Each of said burners is horizontally disposed and located directly abovethe mass of ore upon the bottom 7, the jets of flame therefrom issuingdownwardly. Each is provided-with a central passage or chamber 40,having a series of downwardlyfacing burner orifices or openings 41 onone side thereof, and each is provided with a water-chamber 42,extending from end to end thereof and located above and below thepassage 40. The outer end of each of said burners is formed with atransversely-extending tube or sleeve 43 of the same diameter as thepipe 36, the said sleeve communicating with the central passage andhaving flanges 44 thereon, by means of which it may be bolted orotherwise secured to corresponding flanges on adjacent burners or to theflanges 45 on the pipe 36. Each of said burners is also provided withtransversely-extending tubes or sleeves 46 47, the upper of which isformed with end flanges 48 and the lower of which is formed with endflanges 49. These flanges 48 and 49 are adapted to be bolted orotherwise secured to corresponding flanges on adjacent burners or toflanges 5O 51 on the pipes 52 and 53, respectively. Each of the pipes 52and 53 is formed with two branches which extend along the sides of thefurnace parallel with the branches 36 of the fuel-supply pipe 35, saidpipes 52 and 53 also extending upwardly to a watersupply tank. When thedifferent burners or twyers 34 are connected to each other and to thepipes 52 and 53 in the manner described, the tubes or sleeves 43 willform continua tions of the pipe 36, and the tubes or sleeves 46 and 47will form continuations of the pipes 52 and 53, respectively. As thepipes 52 and 53 are connected with the water-tank and as the chamber 42communicates with the sleeves or tubes 46 and 47, it will be'noted thata holes or perforations water-jacket will be formed around each of theburners or twyers, the circulation being created in the usual manner. Itwill also be noted that a supply of fuel will be delivered through thepipe 35, its branches 36, the tubes or sleeves 13, and the passage 10 tothe burner-orifices 11. As the burner proper,however, is water-jacketed,it will be impossible l for the same to be raised to a red heat or beotherwise overheated. Consequently n0 igi nition of thefuel-gas withinthe burners or twyers can take place. This is a great objection to otherforms of apparatus of this kind. In case the necessity for repairsarises any one or more of the burners or twyers 3 L may be disconnectedfrom the adjacent ones by removing the securing-bolts which hold it inplace and a new one substituted without the necessity for disconnectingany of the other parts of the apparatus. The burners rest near theirouter ends upon the chairs 54, cast or otherwise formed upon base-plate1, and said burners are also provided'with laterally-extending lugs 55,through which and corresponding lugs on the base-plate 1 additionalsecuring-bolts are passed.

I employ in connection with the above parts a distributer 56 for analkaline cooling solution. This distributer is most clearly shown inFigs. 2, 3, 5, 6, 7, and 8 of the drawings. he same comprises a tubularbody having a series of holes or perforations 57 in the bottom thereofand means for controlling the passage through said holes. Said body hasbeen shown as rectangular in cross-section with one corner cut away; butit may be of any other suitable shape, The distributer is horizontallydisposed and extends from front to rear of the furnace, being located inthe space between the inner ends of the burners or twyers 34 and beingbolted to the baseplate 1. The opposite ends of the body thereof haverespectively, connected to them and communicating with the interior ofthe body the pipes-58 and 59, which lead from an elevated tank or othersuitable source of alkali reagent, so that the distributer is keptcharged with said reagent at all times and by the circulation that iscreated the reagent is kept in a comparatively cool condition. The 57are reamed out or otherwise enlarged at their upper ends, and adapted tofit within them are the pins 60, having correspondingly-shaped taperinglower ends, one of such pins being. provided, of course, for each ofsaid openings or perforations. The said pins are all carried by a block61, located within the body of the distributer and mounted for bodilymovement up and down. The said block is guided in its movements by meansof theguide-pins 62,

which extend through openings in said block. 1 Extending through thebody of the distributer 56 and mounted in suitable bearings in the endsthereof isa shaft 63, having a rectangular extension 64 on one of itsprojecting ends adapted for the application of a key or wrench forturning said shaft. WVithin the body of the distributer the shaft 63 isprovided with crank-arms 65, which are connected through the links 66with the block 61, on which the pins 60 are carried. It will thus beseen that by turning the shaft 63 in one direction or the other theblock 61 may be raised or lowered, the latter being guided in a directvertical line by the pins 62. When the block is raised, the pins 60 arelifted from their seats in the holes or perforations 57 and the passagethrough said holes or perforations is opened. Through the latter thealkaline cooling reagent is discharged and of course the degree of thedischarge may be readily controlled and regulated by adjusting theposition of the block 61, which adjustment may be effected by adjustingthe position of the shaft 63. The pins 60 are loosely mounted in theblock 61, so that they are capable of vertical movement independent ofsaid block. The downward movement of each is limited, however, withrespect to said block by a flange or shoulder 67, and same is normallyurged downwardly by means of a coil-spring 68, which fits within arecess in the block 61 and bears against a shoulder at the rear of thehead of the pin. By this construction clogging of one of the holes oropenings 57, which would prevent the entrance of the lower end of thepin 60, which co6perates therewith, will not prevent the other pins fromentering into and closing the openings 57, with which they respectivelycooperate. The end of the shaft 63, which is provided with therectangular extension 6 1, carries a ratchet-wheel 69, with whichcooperates a spring-actuated dog 7 O, mounted upon the end of thedistributer. This dog, acting upon said ratchet, serves to hold theshaft 63 in any position to which it may be turned by a key or wrenchapplied to the rectangular extension 6 1, and consequently holds theblock 61 and the pins 60, which control the passages 57, through whichthe alkaline cooling reagent is discharged, in adjusted position.

From the top of the furnace leads a chimney or flue 71 for the escape ofthe products of combustion and other fumes. This flue is connected witha condenser 72 for recovering from the fumes any of the volatilizedprecious metals which may be carried off therein. The said condenserconsists of a vertically-disposed pipe or conduit 73, to which the flue71 is connected at the upper end. Withinthis conduit is located a pipe74, having a series of spraying .nozzles 75 arranged, at difiierentpoints therein, the said pipe leading from, a tank or other source ofsupply for a suitable liquid cooling and condensing reagent. The lowerend of the conduit 73 fits within a drum 7 6, from the inclined bottomof which leads each of the.

a pipe 77 to a tank 78. The said tank contains near its upper end a pairof parallel screens 79 80, between which is located a mass 81 of crushedcharcoal or other suitable filtering substance. An overflow-opening 82is provided above the upper screen 79, and openings 83 for draw-offplugs are provided beneath the lower screen 80. The pipe 77 eX- tendsthrough the filter and discharges into the tank at a point just belowthe screen 80. Those portions of the fumes which are condensed in theconduit 73 pass down through the drum 76 and pipe 77 into the lower partof the tank 78, which contains water. The heavier particles will ofcourse be precipitated to the bottom of the tank 7 8, and the filter 81will prevent the escape of any condensed particles held in suspensionfrom passing off through the discharge or overflow opening 82. Adjacentto the conduit 73 is a casing or inclosure 84, containing a series offilters arranged one above the other, each consisting of a perforatedsupport 85 and a mass of crushed charcoal or other filtering substance86 thereon. The drum 76 is connected with the lower end of the casing 84by means of a pipe or coupling-piece 87, and a pipe 88 connects thelower end of the casing 84 with the tank 78 at a point in said tankbeneath the screen 80. An escape-flue 89, preferably connected with anexhaust-fan, is provided at the upper end of the casing 84, andextending through the top of said casing are the spraying-nozzles 90,connected, through the pipe 91, with any suitable source of cooling orcondensing reagent. Through the nozzles 90 the liquid reagent issupplied to the various filters in the casing 84, the same acting tokeep such filters in moist condition. Any of the fumes which are notcondensed in the conduit 73 pass through the pipe or couplingpiece 87into the lower end of the casing 84 and then pass upwardly through oneor more of the filters in said casing. These filters serve to morecompletely remove the valuable constituents from the fumes, so thatnothing of real value escapes through the final discharge-flue 89. Suchliquid as may percolate through the various filters and fall to thebottom of the casing 84 passes through the pipe 88 into the tank 78,there to be concentrated in the manner heretofore described. Thefiltering material 86 from each of the supports 85 in the casing 84 maybe removed for the recovery of the valuable substances which accumulatethereon through the openings 92, as may also the filtering material 81in the tank 78.

The operation of my improved apparatus is as follows: Fuel-gas isadmitted to the various burners or twyers 34 through the supplypipe 35,its branches 36, and the tubes 43 on said burners, which formcontinuations of said branches, and ignited at the burner-orifices 41.An oxidizing-flame is produced, and

' ing 6 in the base-plate 1.

by regulating the supply of air mixed with the gas from the producer 37,which may be done by opening or closing the damper 38 to a greater orless degree, a vapor-fuel may be obtained which is of exactly thequality desired. After ignition of the at the burners or twyers 34 thefurnace is allowed to become thoroughly heated up and then is suppliedwith a charge of ore. The ore is preferably broken to about the size ofstove-coal, the exact size being determined by the quality, kind, andcondition of the ore to be treated. This charge is delivered directlyupon the bottom 7 while the latter is at a point removed from thestationary part of the furnace, after which the truck or carriage 8,upon which the bottom 7is mounted, is rolled along the track 10 until itstrikes against the adjustable stop 15. At such time the gear 12 will bein mesh with the worm 13 and the bottom 7 will be directly beneath theopen- A supply of water or the like under pressure is then admittedthrough the pipe 33 to the cylinder 30 of the hydraulic jack, and thepiston 31 thereof is elevated. The latter acts, through the plunger 32,to raise the shaft 11 and the bottom 7 and to hold the latter in itsproper position within the opening 6 in the base-plate l. The worm 13 isthen thrown into operation, and the latter, through the gear 12 on theshaft 11, serves to rotate the bottom 7. The top of the ore is directlybeneath the burners or twyers 34, and as the jets of flame issue fromsaid burners downwardly the said flame is caused to impinge upon theupper surface of the mass of ore and eventually to thoroughly calcinethe same and oxidize the oxidizable portions thereof. When the furnaceis charged in the manner described, the shaft 63 is turned so as toraise the block 61 and the pins 60 carried thereby and open the passagesthrough the holes 57 in the distributer 56. The cooling alkalinesolution in the distributer, which is supplied from the pipe 58, is thendischarged through the holes 57 onto the top of the ore. The action ofthis alkaline solution is twofold: First, it cools down the ore andprevents the temperature from rising to such a degree as wouldvolatilize the precious metals contained therein, and, second, itneutral izes the acids in the ore and prevents the formation of sulfatesand the like on the precious metals. It has the further effect ofintermittently imparting a chilling action to the ore,

I which action serves to disintegrate the same.

The supply of this cooling alkaline solution is continuous; but as thedistributer 56 is fixed in position and the bed of ore is rotated thedifferent parts of the ore will receive the impact of said coolingreagent but twice during each complete rotation of the mass. Theoperation just described is kept up for a suitable length of time, whichmay be determined by the observation of the operator when the ore dizingflame, from above,

the ore from the furnace, the bottom 7 is' lowered by relieving thepressure on the piston 31 of the cylinder 30, and the truck or carriage8 is rolled out of the way to any suitable point on the rails 10. Theore may be dumped from the bottom by releasing the bolt 29, which holdsthe gate or door 27 in place and allowing the latter to fall. Allvaluable constituents of the fumes are removed in the manner heretoforedescribed.

Having described my invention, I claim- 1. In an apparatus for treatingrefractory ores, a furnace-chamber, a series of burners or twyerstherein provided with means for subjecting the ore in said furnace to anoxiand means for supplying to the ore in said furnace an alkalinecooling reagent.

2. In an apparatus for treating refractory ores, a furnace-chamber, aseries of burners or twyers therein, arranged in rows, having theirdischarge-orifices directed downwardly for subjecting the ore in thefurnace to an oxidizing-flame, from above, and an elongated hollowliquid-distributor located in said furnace in the space between the rowsof burners.

3. In an apparatus for treating refractory ores, a furnace-chamber, aseries of burners or twyers therein, connected with a suitable source offuel, arranged in rows extending from opposite sides of said chamber,and terminating at their inner ends adjacent to a diametrical linethrough said chamber, and an elongated tubular liquid-distributer insaid furnace located in the space between the ends of the rows ofburners.

In an apparatus for treating refractory ores, a furnacechamber, a rotarybottom therefor, a series of burners or twyers arranged in rows in saidchamber, the inner ends of said burners terminating adjacent to adiametrical line through said chamber, and a hollow stationaryliquid-distributer located in the space between the inner ends of saidrows of burners.

5. In an apparatus for treating refractory ores, the combination with afurnace-chamber and means for roasting ores therein, of aliquid-distributer in said chamber comprising a hollow body connectedwith a source of liquid-supply and provided with a series ofdischarge-openings, and adjustable means in said openings forcontrolling the discharge of liquid therethrough.

6. In an apparatus for treating refractory ores, the combination with afurnace-chamber and means for roasting ores therein,ofaliquiddistributer in said chamber comprising a hollow body connectedwith asource of liquid-supply and provided with a series ofdischargeopenings, plugs or pins controlling the passages through saidopenings, and means for adjusting the position of said plugs forcontrolling the discharge.

7. In an apparatus for treating refractory ores, the combination with afurnace-chamber and means for roasting ores therein,ofaliquiddistributor in said chamber comprising a hollow body connectedwith a source of liquid-supply and provided with a series of dischargeopenings in its bottom, plugs or pins controlling the passages throughsaid openings, a block upon which said plugs are severally mounted andmeans for regulating the position of said block and thereby controllingthe passages through said openings.

8. In an apparatus for treating refractory ores, the combination with afurnace-chamber and means for roasting ores therein,of aliquiddistributer in said chamber comprising a hollow body connectedwith a sourceof liquid-supply and provided with a series ofdischargeopenings in its bottom, plugs or pins controlling the passagesthrough said openings, a bodily-movable block on which said plugs areseverally mounted, a guide for controlling the movements of said blockand means for-adjusting the position of said blocks for controlling thepassages through said openings.

9. In an apparatus for treating refractory ores, the combination with afurnace-chamber and means for roasting ores therein,of aliquiddistributer in said chamber comprising a hollow body connectedwith a source of liquid-supply and provided with a series ofdischargeopenings in its bottom, a vertically-movable block in said bodyhaving recesses therein, a series of plugs or pins for controlling thepassages through said openings, said plugs having heads thereon whichfit in said recesses, and contracted shanks which extend throughopenings in said block, springs in said recesses for normally urgingsuch plugs downwardly with respect to said block, means for limitingthis downward movement and means for adjusting the position of saidblock and thereby controlling, through said pins, the passages throughsaid openings.

10. In an apparatus fortreating refractory ores, the combination with afurnace-chamber and means for roasting ores therein,of aliquiddistributer in said chamber comprising a hollow body connectedwith a source of liq uid-su pply and provided with a series ofdischargeopenings in its bottom, plugs or pins controlhug the passagesthrough said openings, at

bodily-movable block on which said plugs are severally mounted, a shaftmounted for turning movement in the ends of said body, crankarms on saidshaft connected with said block, and means for locking said shaft in anyposition to which it may be turned.

11. In an apparatus for treating refractory ores, the combination withafurnace-chamber and means for roasting ores therein,of aliquiddistributer in said chamber comprising a hollow body connectedwith a source of liquidsupply and provided with a series ofdischargeopenings in its bottom, plugs or pins controlling the passagesthrough said openings, a bodily-movable block on which said plugs areseverally mounted, a shaft mounted for turning movement in said body, aratchet-wheel on said shaft, a dog on the body cooperating therewith,means for turning said shaft, and crank-arms connecting said shaft withsaid block.

12. In an apparatus for treating refractory ores, the combination withan elevated furnace-chamber having an opening in the lower part thereof,of a bottom for said chamber adapted to fit within said opening, abodilymovable truck or carriage on which said bottom is mounted andmeans for raising and lowering said bottom, independently of said truck,into and out of said opening.

13. In an apparatus for treating refractory ores, the combination withan elevated furnace-chamber having a circular opening in the lower partthereof, of a circular bottom adapted to fit within said opening, abodilymovable truck or carriage on which said bottom is mounted, meansfor raising and low ering said bottom independently of said truck andmeans for rotating it.

14. In an apparatus for treating refractory ores, the combination withan elevated furnace-chamber having a circular opening in the lower partthereof, of a trackway beneath said chamber, a truck or carriage movableon said trackway, a vertical shaft mounted for rotation on said truck, acircular bottom for said furnace-chamber secured to and supported uponsaid shaft and adapted to fit within said opening, and means for raisingand lowering said shaft and the bottom carried thereby, independently ofsaid truck.

15. In an apparatus for treating refractory ores, the combination withan elevated furnace-chamber having a circular opening in the lower partthereof, of a trackway beneath said chamber, a truck or carriage movableon said trackway, a vertically-movable shaft mounted for rotation onsaid truck, a vertically-immovable worm-gear carried by said truck andkeyed to said shaft, aworm adapted to mesh with said gear for turningit, means for raising and lowering said shaft and holding it in raisedposition and a circular bottom for said chamber mounted upon the upperend of said shaft and adapted to fit within said opening.

In witness whereof Isubscribe my signature in the presence of twowitnesses.

JULIUS LEEDE.

Witnesses:

FRANK S. OBER, Wu. M. STOCKBRIDGE.

